豫东潮土区近14年土壤肥力和作物产量的演变及其对施肥的响应

Soil fertility and crop yield variation and their response to fertilization in the fluvo-aquic soil regions of east Henan Province from 2006 to 2019

【目的】土壤肥力是作物产量的基础和科学施肥的重要依据。本研究分析了豫东潮土区长期定位试验最近14年的监测数据,以明确常规化肥施用模式下农田土壤肥力和作物产量的演变特征及其对施肥的响应,为潮土区农田科学合理施肥及农业可持续发展提供理论依据。【方法】数据来自河南商丘实验站6个定位监测点,基于2006—2019年对0—20、20—40 cm土层9个土壤肥力指标(有机质、全氮、全磷、碱解氮、有效磷、速效钾、缓效钾、pH、土壤容重)的监测结果以及农田施肥量和作物产量的调查结果,运用修正的内梅罗指数法对土壤肥力进行了评价,采用通径系数方法分析农田氮磷钾化肥施用量对土壤肥力和作物产量贡献的影响。【结果】6个农田监测点0—20土层土壤有机质、全氮、全磷、碱解氮、速效钾和缓效钾含量及土壤综合肥力指数(IFI)均逐渐增加,2019年较2006年分别增加了84.1%、165.0%、28.0%、57.0%、61.6%、277.3%、0.37,速效磷含量总体变化不显著;20—40 cm土层土壤有机质、全磷、碱解氮、速效钾和缓效钾含量及IFI总体表现为逐渐增加,全氮、速效磷含量呈先增加后降低趋势;0—10、10—20 cm土层土壤容重提高。14年间,氮、磷化肥和氮磷钾化肥总施用量呈增加趋势,2019年较2006年分别增加了79.0%、186.0%和73.8%。2019年小麦和玉米总产量较2006年增加了4.2%,作物产量增幅明显小于化肥投入量的增幅。通径分析结果表明,2006—2009年间氮、磷、钾化肥对土壤肥力的贡献值分别为0.718、0.710、0.710,对作物产量的贡献值分别为1.091、1.087、1.087,而2010—2019年间对土壤肥力的贡献值分别为0.523、0.364、−0.620,对作物产量的贡献值分别为0.911、0.884、−1.108,明显低于2006—2009年。【结论】从2006到2019年的14年间,豫东潮土区农田化肥施用量增加了73.8%,而农作物产量仅增加了4.2%,且氮磷钾化肥对土壤肥力和作物产量的贡献呈降低趋势。14年间0—20 cm土层土壤pH无明显变化,土壤综合肥力指数总体处于中等水平,0—20 cm土层土壤结构趋于紧实板结,2010年以后的氮磷钾化肥用量对耕层土壤紧实板结有显著影响,需进一步研究适当减少氮磷钾化肥施用量、改善土壤通透性的施肥措施。

【Objectives】Soil fertility is the foundation for efficient crop production and scientific fertilization.The soil fertility and crop yield were monitored using a long-term experiment,to clarify their response to fertilization in the east Henan Province.【Methods】Shangqiu City is located in the east part of Henan Province,where most farmland is fluvo-aquic soil.The long-term fertilization experiment in Shangqiu consists of 6 monitoring sites around the city,the soil samples in 0−20 cm and 20−40 cm layers were collected every year from all the monitoring sites for the determination of organic matter(OM),total nitrogen(TN),total phosphorus(TP),alkali hydrolyzable nitrogen(AN),available phosphorus(AP),available potassium(AK),slowly available potassium(SK),pH,and soil bulk density from 2006 to 2019.At the same time,the nitrogen,phosphorous,and potassium fertilizer input and crop yield were investigated.The soil fertility were evaluated using the modified Nemero index method,and the fertilizer contribution to soil fertility and crop yield were calculated using the path coefficient method.【Results】During the 14 years from 2006 to 2019,the soil OM,TN,TP,AN,AK and SK,and the soil comprehensive fertility index(IFI)tended to increase in 0−20 cm soil layers,with the increase rate of 84.1%,165.0%,28.0%,57.0%,61.6%,277.3%,and 0.37,respectively,while the AP did not changed signi-ficantly.The OM,TP,AN,AK and SK and IFI in the 20−40 cm soil layer kept increasing,and the TN and AP increased first and then decreased.The bulk density was in an increased trend in the 0−10 cm and 10−20 cm soil layers.The application amount of N and P fertilizers and the total amount of chemical fertilizers increased by 79.0%,186.0%and 73.8%,respectively,and that of K fertilizer increased first and then decreased over the 14 years.The total output of wheat and maize was increased only by 4.2%over the 14 years,which was significantly lower than the increase of chemistry fertilizer input.According to the Path analysis,the contribution values of N,P and K fertilizers to soil fertility were 0.718,0.710,and 0.710,and to crop yield were 1.091,1.087,and 1.087 from 2006 to 2009.While the contribution to soil fertility was 0.523,0.364,and−0.620,and that to crop yield were 0.911,0.884,and−1.108 from 2010 to 2019 year,obvious lower than that from 2006 to 2009.【Conclusions】During the 14 years period from 2006 to 2019,the chemical fertilizer input increased by 73.8%,while the crop yield increased by 4.2%,the contribution of N,P and K fertilizer input to soil fertility and crop yield showed a decreasing trend.The soil pH did not change obviously and the IFI was generally in middle level in 0−20 cm layer.The topsoil layer tended to be compacted and consolidated due to over application of chemical fertilizers after 2010.More study should be conducted to reduce chemical fertilizer input and alleviate soil compaction in the future.